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Wednesday, January 26, 2011

Genealogist's View -- More about memory cards

The names chosen by the manufacturers of memory cards are not helpful. They seldom give you any idea what the product is or can do. Since, in my experience, genealogists are consumers of flash memory and purchase digital cameras, it would be convenient to know what you are looking at when making a purchase without doing a search on the Internet. Unfortunately the memory card landscape is just about as complicated as buying a new car (although they cost a whole lot less than cars). I think this post on memory cards will turn out to be a series. My first post was called "Moving Data -- Genealogist's View of Memory Cards." This post picks up where that one left off.

Before you purchase a digital camera, it is very important to understand what type of memory card the camera uses. You should consider the availability, cost and maximum capacity of the cards. Frequently, a memory card is included in the initial purchase of the camera, but like OEM (original equipment manufacturer) tires on a car, the cards are not usually what you want in the long run. Each memory card has a specific amount of flash memory and will take a certain number of pictures. The number of pictures is determined by the settings on the camera. More expensive cameras have menu settings allowing the user to specify the resolution of the picture. The higher the resolution the larger the photo's file size, the lower the resolution the smaller the size. Each memory card is sort-of like having another roll of film for your camera. When a card fills up with photos, you either have to delete photos by transferring them to your computer or printing them off, or by putting in a new unused card.

Caution Number One: Don't leave photos on the memory card in your camera for an extended period of time without downloading them to your computer.

One problem caused by leaving photos in the camera is that the next time you want to take pictures, the memory card may be nearly full and you will metaphorically run out of film. Professional photographers advise removing the card from the camera to download the photos. This requires a card reader, another device, that can be hooked up to your computer. One reason for not using the camera to transfer the photos, is that if the camera's battery fails during the transfer, photos may be lost. Camera batteries have a tendency to run out at the most inopportune times. I always carry extra batteries or a fully charged spare.

So let's run through a picture taking session. You want a picture of little Johnny sitting in his high chair. You get out your digital camera and go to take a picture. The camera says "Memory Card Full." You rummage through your drawers and shelves looking for another memory card or you run to the computer and start to download all the photos you took previously. By the time you get back, little Johnny is graduating from High School.

Somewhere in the documentation for your camera, or on the manufacturer's website, there will be a table showing how many pictures you can expect to take with any given resolution and any given size of memory card. Because the cards are relatively inexpensive, it is a good idea to have several available and make sure all the photos have been transferred and the cards erased. Professional photographers also recommend that you format the card (erase the pictures) using the camera's formatting program, of course, after transferring and backing up all the photos. Using your computer to erase the cards or manage the pictures on the card could possibly make the card unreadable by your camera.

Caution Number Two: Back up all your photos before starting to edit or print them.

This seems to be common sense. But how many of us follow this advice? I admit I don't always make a back up. However, on my computer, an Apple iMac, I have an automatic backup to an external 2 Terabyte drive every few hours to Time Machine. Which, by the way, works very well.

1 comment:

This is an excellent series of posts! As a tech guy, I'm always tempted to add a comment to "clarify" things, but each time I've stopped myself as I think you've done a good job of explaining these memory cards for non-technical users, where I would have included a little too much information, causing confusion.

The only thing I will add here is that from my viewpoint, it appears SD (and variants Mini-SD and Micro-SD) are winning the standard war. Most mobile phones use some form of the SD standard, most low- to medium price cameras and even some of the higher end cameras now use it as well. Many new computers and laptops now come with SD card readers built-in, making it really easy to handle the data transfers.